Chaetochromins B, C and D, Bis (naphtho-γ-pyrone) Derivatives from Chaetomium gracile

Abstract

Besides chaetochromin A (1), a known mycotoxin and antitumor agent, three related bis (naphtho-γ-pyrone) derivatives named chaetochromins B (2), C (3), and D (4) were isolated from Chaetomium gracile. The structures were elucidated as the diastereomer, the 3-demethyl derivative, and the 2, 3-dehydro derivative of 1, respectively, chiefly on the basis of nuclear magnetic resonance data.